"The basis of Sufism is consideration of the hearts and feelings of others. If you haven't the will to gladden someone's heart, then at least beware lest you hurt someone's heart, for on our path, no sin exists but this." Dr. Javad Nurbakhsh, Master of the Nimatullahi Sufi Order.

"To those who are good to me, I am good; to those who are not good to me, I am also good. Thus all get to be good."

"The sage has no interest of his own, but takes the interests of the people as his own. He is kind to the kind; he is also kind to the unkind: for Virtue is kind. He is faithful to the faithful; he is also faithful to the unfaithful: for Virtue is faithful." Tao Teh Ching, Chapter 49.

Unitarian Universalism (referred to as Unitarianism in some countries):

"The inherent worth and dignity of every person;"

"Justice, equity and compassion in human relations.... "

"The goal of world community with peace, liberty, and justice for all;"

"We affirm and promote respect for the interdependent web of all existence of which we are a part." Unitarian principles. 1,2

"When any one questions whether what he plans to do to another will be done in accordance with the law of nature or not, let him imagine himself in the other man’s place."

Kant: "Act as if the maxim of thy action were to become by thy
will a universal law of nature." (Germany; 18th century CE)

John Stuart Mill: "To do as you would be done by, and to love your neighbor as yourself, constitute the ideal perfection of utilitarian morality." (Britain; 19th century CE)

Examples from moral/ethical systems are:

Humanism:

"...critical intelligence, infused by a sense of
human caring, is the best method that humanity has for resolving problems.
Reason should be balanced with compassion and empathy and the whole person
fulfilled." Humanist Manifesto II; Ethics section.

"(5) Humanists acknowledge human interdependence, the need for mutual respect and the kinship of all humanity."

"(11) Humanists affirm that individual and social problems can only be resolved by means of human reason, intelligent effort, critical thinking joined with compassion and a spirit of empathy for all living beings." 3

"Don't do things you wouldn't want to have done to you, British Humanist Society.

Scientology:

"20: Try to treat others as you would want
them to treat you." This is one of the 21 moral precepts that form
the moral code explained in L. Ron Hubbard's booklet "The Way to
Happiness." 4

Other sources:

The Yorubas of West Africa: "He who injures another injures himself." The Yoruba people in southwestern Nigeria and surrounding areas of West africa. Santería, Umbanda, and Candomblé evolved from the Yoruba religion.

Moroccan tribesmen:

"He who has done something will have it done to him."

"He who sows good will reap peace."

"What you desire for yourself you should desire for others."

Bakongo (a.k.a. Kongo people; an ethnic group found in West Africa from the Repubilc of Congo to Angola):

"If you see a jackal in your neighbor's garden, drive it out. One might get into yours one day, and you would like the same done for you."

"O man, what you do not like, do not toy our fellows."

From the Upanishads -- the foundational document for Indian Brahmanism (circa 700 BCE):

"Let no man to do another that which would be repugnant to himself; this is the sum of righteousness. A man obtains the proper rule by regarding another's case as like his own." 5

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